The National Institute for Biotechnology in the Negev, Ben Gurion University, Beer-Sheva, Israel.
Mol Biol Evol. 2011 Jan;28(1):551-65. doi: 10.1093/molbev/msq226. Epub 2010 Aug 26.
The GDSL-lipase gene family is a very large subfamily within the supergene family of SGNH esterases, defined by the distinct GDSL amino acid motif and several highly conserved domains. Plants retain a large number of GDSL-lipases indicating that they have acquired important functions. Yet, in planta functions have been demonstrated for only a few GDSL-lipases from diverse species. Considering that orthologs often retain equivalent functions, we determined the phylogenetic relationships between GDSL-lipases from genome-sequenced species representing bryophytes, gymnosperms, monocots, and eudicots. An unrooted phylogenetic tree was constructed from the amino acid sequences of 604 GDSL-lipases from seven species. The topology of the tree depicts two major and one minor subfamily. This division is also supported by the unique gene structure of each subfamily. Because GDSL-lipase genes of all species are present in each of the three subfamilies, we conclude that the last common ancestor of the land plants already possessed at least one ancestral GDSL-lipase gene of each subfamily. Combined gene structure and synteny analyses revealed events of segmental duplications, gene transposition, and gene degeneration in the evolution of the GDSL-lipase gene family. Furthermore, these analyses showed that independent events of intron gain and loss also contributed to the extant repertoire of the GDSL-lipase gene family. Our findings suggest that underlying many of the intron losses was a spliceosomal-mediated mechanism followed by gene conversion. Sorting the phylogenetic relationships among the members of the GDSL-lipase gene family, as depicted by the tree and supported by synteny analyses, provides a framework for extrapolation of demonstrated functional data to GDSL-lipases, whose function is yet unknown. Furthermore, function(s) associated with specific lineage(s)-enriched branches may reveal correlations between acquired and/or lost functions and speciation.
GDSL 脂肪酶基因家族是 SGNH 酯酶超基因家族中的一个非常大的亚家族，其特征是独特的 GDSL 氨基酸基序和几个高度保守的结构域。植物保留了大量的 GDSL 脂肪酶，表明它们已经获得了重要的功能。然而，只有少数来自不同物种的 GDSL 脂肪酶在植物体内的功能得到了证实。考虑到同源物通常保留等效的功能，我们确定了来自代表苔藓植物、裸子植物、单子叶植物和真双子叶植物的基因组测序物种的 GDSL 脂肪酶之间的系统发育关系。从 7 个物种的 604 个 GDSL 脂肪酶的氨基酸序列构建了无根系统发育树。该树的拓扑结构描绘了两个主要和一个次要亚家族。这种划分也得到了每个亚家族独特基因结构的支持。由于所有物种的 GDSL 脂肪酶基因都存在于这三个亚家族中的每一个中，我们得出结论，陆地植物的最后共同祖先已经拥有了每个亚家族的至少一个祖先 GDSL 脂肪酶基因。结合基因结构和基因同线性分析揭示了 GDSL 脂肪酶基因家族进化过程中的片段重复、基因转位和基因退化事件。此外，这些分析表明，内含子获得和丢失的独立事件也促成了 GDSL 脂肪酶基因家族现存的基因库。我们的研究结果表明，许多内含子丢失的原因是剪接体介导的机制，随后是基因转换。根据树状图和基因同线性分析对 GDSL 脂肪酶基因家族成员的系统发育关系进行分类，为将已证实的功能数据外推到功能未知的 GDSL 脂肪酶提供了一个框架。此外，与特定谱系富集分支相关的功能可能揭示获得和/或丢失的功能与物种形成之间的相关性。
